Exemplary embodiments of the present invention relate to a mobile fuel filter and method for the removal of sulfur containing compounds from a diesel fuel. More particularly, exemplary embodiments relate to a mobile fuel filter and method for the removal of sulfur containing compounds that provide for the production of fuel streams having concentrations of sulfur containing compound of less than 15 ppm.
There continues to be environmental concern relating to air pollution stemming from use of internal combustion engines, especially those used in transportation applications such as cars, trucks, boats and the like, and stationary power sources such as diesel generators and the like. In addition to being a direct source of pollution in the form of SOx, sulfur also poisons the catalytic surface of exhaust after treatment devices. By reducing sulfur in the fuel and therefore the exhaust, the useful life of exhaust after treatment devices is extended.
New power sources such as fuel cells will also require fuel streams to have similar or lower levels of sulfur. Fuel cells burn hydrogen that has been reformed from various hydrocarbon fuels, such as gasoline. Sulfur will poison the active surfaces of the fuel cell, thus shortening its life.
As a result, various governments and regulatory bodies continue to enact legislation intended to substantially lower the acceptable levels of sulfur and sulfur containing compounds present in the fuels used in internal combustion engines.
The U.S. EPA, for instance, has enacted regulations requiring diesel fuel producers to phase in the production of low sulfur diesel fuel (equal to or less than 15 ppm sulfur) beginning in 2006 and ending in 2010. Similarly, from 2004 to 2006, gasoline sulfur levels were reduced from 50 ppm to 30 ppm. The need for commercially available fuels having continually lower levels of sulfur containing compounds creates new problems for the manufacturers, of such fuels, i.e., the refining industry as well as the distributors and direct sellers of commercial fuels. In some cases, the refining industry may be unable to provide post refinery fuels having levels of sulfur containing compounds in accordance with recently enacted legislation. In other cases, a refinery may have produced fuel that was initially at an acceptable level but which subsequently became contaminated at some point enroute to the distributor and/or direct seller. In all such cases, the commercially available fuel may require additional removal of sulfur containing compounds.
The refining industry has used several different approaches for removing sulfur from commercially available fuel feedstocks such as gasoline and diesel.
The most common methods employed by the refinery industry for the removal of sulfur from fuels are hydrodesulfurization (HDS), Merox thiol extraction processing, and adsorption.
However, such processes continue to be unable to produce cost effective commercially available fuels that have acceptable levels of sulfur containing compounds.
Moreover, providing additional removal of sulfur containing compounds from the commercially available fuel may require the need to return the non-compliant fuel back to, for example, the refinery for reprocessing, which can be costly. Furthermore, the need for reprocessing the non-compliant fuel may cause extensive interruption to the supply of fuel to the customer.
As a result, it is now recognized that there is a need for the development of processes and apparatus capable of removing sulfur containing compounds from fuel feedstocks that have already been subjected to sulfur removing processes by the manufacturer of the fuel feedstock, i.e., a refinery. These processes and apparatus employed with regards to post refinery fuels may be referred to as ‘sulfur polishing’ processes and/or apparatus.
Since post refinery fuel feedstocks have reduced levels of sulfur containing compounds, such sulfur polishing technology must be capable of producing fuels having particularly low concentrations of sulfur containing fuels, i.e., less than 50 ppm and more particularly less than 15 ppm.
It would advantageous if an end user or consumer of a commercially available fuel could readily and easily provide on-the-spot fuel remediation without the need to return the fuel for reprocessing, thus reducing the cost of non-compliance and preventing extensive interruption to the supply of fuel to the customer.
It would be advantageous if sulfur-polishing technology were suitable for use in the normal fuel distribution systems employed by refineries to distribute their manufactured product. The components of such fuel distribution systems may be generally referred to as interim storage devices, i.e., above and below ground storage tanks, tanker trucks, connecting piping, metering and dispensing equipment, and the like.
It would also be especially advantageous if an end user or consumer of a commercially available fuel could readily and easily employ a sulfur polishing technology.
Accordingly, it is desirable to provide a mobile filter that provides on-the-spot fuel remediation. It is also desirable to provide a mobile filter that can filter fuel from a storage device having a holding capacity of greater than 1000 gallons. It is also desirable to provide a mobile filter unit that produces fuel streams having concentrations of sulfur containing compound of less than 15 ppm and a method for providing the same. Other desirable aspects of the present invention will become apparent with the description below.